End mill
An end mill includes: an end mill body configured to be rotatable around an axis; a chip discharge groove configured to extend from a tip in an axial direction of the end mill body toward a rear end side in the axial direction while twisting around the axis; and outer peripheral cutting edges each being configured to be formed at an intersection ridge portion on a forward side in a rotation direction between the chip discharge groove and an outer peripheral flank face. At least one outer peripheral cutting edge includes a plurality of notch portions that discontinue the outer peripheral cutting edge. Circumferential positions of all the notch portions in the end mill body do not overlap each other.
1 . An end mill comprising:
an end mill body configured to be rotatable around an axis;
chip discharge grooves configured to extend from a tip side in an axial direction of the end mill body toward a rear end side in the axial direction while twisting around the axis; and
outer peripheral cutting edges each being configured to be formed at an intersection ridge portion on a forward side in a rotation direction between the chip discharge groove and an outer peripheral flank face,
wherein at least one outer peripheral cutting edge includes a plurality of notch portions that discontinue the outer peripheral cutting edge,
each of the notch portions is a recessed groove extending in a circumferential direction with a non-cutting region on an extension line of the outer peripheral cutting edge, and
when viewed in the axial direction, the notch portions do not overlap with each other across the entire recessed groove of each notch.
2 . The end mill according to claim 1 ,
circumferential positions from a front end to a rear end in the rotation direction of all the notch portions in the end mill body do not overlap each other.
3 . The end mill according to claim 1 ,
wherein among spacings between front ends in the rotation direction of two notch portions adjacent in a circumferential direction, at least one spacing is different from the other spacings.
4 . The end mill according to claim 1 ,
wherein a blade length is equal to or more than two times a blade diameter.
5 . The end mill according to claim 1 ,
wherein five or more outer peripheral cutting edges are provided.
6 . The end mill according to claim 1 ,
wherein twist angles of all the outer peripheral cutting edges are 35° or more.
7 . The end mill according to claim 1 ,
wherein the notch portions are disposed such that among continuous blade lengths which continue in an extending direction of the outer peripheral cutting edges, a maximum continuous blade length in the end mill body is equal to or less than three times a blade diameter.
8 . The end mill according to claim 1 ,
wherein the notch portions are disposed such that among continuous blade lengths which continue in an extending direction of the outer peripheral cutting edges, a minimum continuous blade length in the end mill body is equal to or more than 0.6 times a blade diameter.
9 . The end mill according to claim 1 ,
wherein twist angles of all the outer peripheral cutting edges are equal to each other.
10 . The end mill according to claim 1 ,
wherein each of the notch portions is disposed such that the other notch portion closest to the notch portion in axial position is a different notch portion from the other notch portion closest to the notch portion in circumferential position.
11 . The end mill according to claim 1 ,
wherein the outer peripheral cutting edges are rightward twisted, and all the notch portions are disposed such that among two of the notch portions which are adjacent in axial position, the notch portion located on the rear end side is located forward in the rotation direction with respect to the notch portion located on the tip side.